54 lines
1.8 KiB
Rust
54 lines
1.8 KiB
Rust
//! Name resolution for lifetimes: type declarations.
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use crate::ty;
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use rustc_data_structures::fx::{FxHashMap, FxHashSet};
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use rustc_hir::def_id::{DefId, LocalDefId};
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use rustc_hir::ItemLocalId;
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use rustc_macros::HashStable;
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#[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable, Debug, HashStable)]
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pub enum Region {
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Static,
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EarlyBound(/* index */ u32, /* lifetime decl */ DefId),
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LateBound(ty::DebruijnIndex, /* late-bound index */ u32, /* lifetime decl */ DefId),
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Free(DefId, /* lifetime decl */ DefId),
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}
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/// A set containing, at most, one known element.
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/// If two distinct values are inserted into a set, then it
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/// becomes `Many`, which can be used to detect ambiguities.
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#[derive(Copy, Clone, PartialEq, Eq, TyEncodable, TyDecodable, Debug, HashStable)]
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pub enum Set1<T> {
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Empty,
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One(T),
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Many,
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}
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impl<T: PartialEq> Set1<T> {
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pub fn insert(&mut self, value: T) {
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*self = match self {
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Set1::Empty => Set1::One(value),
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Set1::One(old) if *old == value => return,
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_ => Set1::Many,
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};
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}
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}
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pub type ObjectLifetimeDefault = Set1<Region>;
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/// Maps the id of each lifetime reference to the lifetime decl
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/// that it corresponds to.
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#[derive(Default, HashStable, Debug)]
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pub struct ResolveLifetimes {
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/// Maps from every use of a named (not anonymous) lifetime to a
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/// `Region` describing how that region is bound
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pub defs: FxHashMap<LocalDefId, FxHashMap<ItemLocalId, Region>>,
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/// Set of lifetime def ids that are late-bound; a region can
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/// be late-bound if (a) it does NOT appear in a where-clause and
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/// (b) it DOES appear in the arguments.
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pub late_bound: FxHashMap<LocalDefId, FxHashSet<LocalDefId>>,
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pub late_bound_vars: FxHashMap<LocalDefId, FxHashMap<ItemLocalId, Vec<ty::BoundVariableKind>>>,
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}
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